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What are Algal Blooms?
ONC Editorial

Aug 28, 2023

Explaining the adverse environmental and economic effects of algal blooms.

Algal blooms are algae overgrowth that cover bodies of water. They usually result from excess nutrients in the water, such as nitrogen and phosphorus, which cause these plants to propagate uncontrollably. 

This nutrient pollution can come from stormwater, wastewater and/or agricultural runoff. Each of these sources accumulates contaminants as it moves, delivering them to our water sources. Additionally, excess nitrogen in the air can instigate algal growth.

Algal blooms in excess are harmful to the health of people, wildlife and the environment, as many produce extremely dangerous toxins. Exposure to contaminated water can cause rashes, stomach and liver problems, respiratory issues and neurological defects. 

It can also have disastrous effects on wildlife. Algae overgrowth can limit the ability of fish and other marine wildlife to find food, as it produces a thick cover over the surface of a body of water. This blocks sunlight, forcing entire species to leave the area or die. 

Also, when small fish consume toxic algae, it moves up the food chain and can eventually reach large mammals, including humans, causing serious harm. 

Economically, algal blooms destroy landscapes and can have a pungent stench, which can reduce waterfront property value. They also negatively impact tourism, raise drinking water and seafood costs and inhibit the fishing industry. 

Local, state and federal governments spend billions of taxpayer dollars every year to try and mitigate the adverse effects of algal blooms on people and the environment. As climate change and agricultural practices become more widespread, so will algal blooms. 

Annie Llombart is a University of California Santa Cruz graduate with majors in Politics and Environmental Studies and a minor in History. She focused her studies on environmental policy, international relations and sociology. She has also worked at the United Nations with the Spanish delegation on the 2030 Agenda for Sustainable Development and as sustainability coordinator for Fundación Alternativas, a Spanish think tank. She is currently a law school candidate and seeks to pursue a degree in environmental law to further her commitment to protecting our world’s resources.


“Harmful Algal Blooms.” EPA, Environmental Protection Agency,

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